St. Louis-based brewer Anheuser-Busch describes its Bud Light Lime-A-Rita as having “the great taste of a margarita with a twist of Bud Light Lime for a delightfully refreshing finish.”

The beverage's list of ingredients include water, barley malt, dextrose syrup, corn or rice, high fructose corn syrup, citric acid, sodium citrate, natural and artificial flavors, caramel color, hop extract, and yeast. An 8-oz. can contains 220 calories and 21.9 grams of carbohydrates, and says so on the side of the label.

But is Bud Light Lime-A-Rita really “light?"

That depends on what you compare it to. It's lighter than any beverage that has more than 220 calories. On the other hand, any beverage containing fewer than 220 calories is lighter.

Clearly, lightness is relative. In court, the relative lightness of an 8-oz. can or 12-oz. bottle of Lime-A-Rita is something that could be stipulated.

On the other hand, how light is Sheila Cruz? That may be a matter of conjecture, but it is also a matter of relationship.

Ms. Cruz is undoubtedly lighter than some women her own age and height, and heavier than others. The number of Lime-A-Ritas consumed would contribute, more than likely, to the degree of lightness or un-lightness.

In any case, it's safe to say that Cruz is considerably heavier than an 8-oz. Lime-A-Rita. It may be enviousness of that relatively light can that's driving her litigation.

Last month she filed a class action suit in Los Angeles against Anheuser-Busch, claiming its Lime-A-Ritas are deceptively marketed as “light.”

Cruz points out that the Lime-A-Rita has more calories than any other AB product – which did not require much detective work, what with the calorie counts being posted on all product labels.

Not much is to be learned from comparing apples and oranges, however. What is worth noting is that a Lime-A-Rita has about half the calories of a traditional margarita. For a meaningful comparison, you have to have the right cans.

You also have to have time on your hands, a lawyer with the same, and a fondness for the nanny state. If you need the government to tell you whether an alcoholic drink is “light,” calorie counts are surely the least of your problems.